The present disclosure relates to a method for controlling the temperature of at least one battery element, a battery and a motor vehicle with such a battery, which can especially be used in order to prevent damage to the at least one battery element during charging or discharging of the at least one battery element.
A lithium-ion battery is a rechargeable electrical energy storage device, which is widely used in cell phones, laptops, portable consumer equipment etc. In automobile applications, lithium-ion batteries represent a key technology for the electrification of the drive system. Depending on customer requirements, different solutions can be developed, e.g. partial electrification is implemented in hybrid vehicles (HEV), and 100% electrical energy from lithium-ion batteries is used in (pure) electrical vehicles (EV). The lithium-ion batteries can, depending on operating specifications, be of modular construction and are electrically wired in series or in parallel. The battery can generally be charged both by means of the electric motor and also by means of a connection to an external network.
A significant aspect for a successful establishment of said technology is inter alia the operational safety of lithium-ion batteries. Here it is necessary to operate the battery within an optimal temperature range. This is because the battery temperature has a great influence on the provision of power, ageing (power reduction) or service life and operational safety (danger of fire). The result of this is that a well-considered thermal management concept is essential for the use of lithium-ion batteries in vehicles.
For automobile applications it is important to protect lithium-ion batteries against overheating and to prevent undercooling. A thermal management system ensures this with the necessary temperature measurement or monitoring and effective countermeasures.
With lithium-ion batteries the efficiency when charging and discharging is temperature-dependent, so e.g. at low temperatures the battery enables a significantly lower charging current or discharging current than if the battery is in an optimal operating temperature range. The result of this is that charging the battery in the winter or in cold weather below the freezing point takes significantly longer and the starting capability of the electrical vehicle or hybrid vehicle can be considerably delayed.
Moreover, a charging current or discharging current that is too high at low temperature results in irreversible damage to lithium-ion cells, so that safe operation can no longer be permanently guaranteed.
A method for determining the temperature of a vehicle battery is described in the publication DE 198 06 135 A1, wherein the temperature is calculated indirectly depending at least on the engine temperature and the ambient temperature.
A method for the operation of vehicles is known from the publication DE 10 2009 046 568 A1, whereby the temperature management of the vehicle battery takes place depending on the load profile associated with a route.